FLSUN V400 tool for adjusting the belt tension

The FLSUN V400 user manual recommends adjusting the tension of the toothed belts every 2 months. But how can the toothed belt tension be measured reproducibly?

I have found 2 tools that use the spring force of a 3D printout as their functional principle. However, this spring force depends on the filament used, infill type and density, as well as the number of walls - all in all a rather random result.

My idea: A lever construction with defined, customizable leverage.

I use 50 cent coins as weights. A 50 cent coin weighs 7.8 grams.

The correct toothed belt tension is indicated by a pointer that is vertical and parallel to the printer frame. In my case, this is achieved with 6 50 cent coins, i.e. 46.8 grams in weight.

IMPORTANT: Make sure that the extruder is in the home position (at the top) when measuring or setting. The tool should be attached at medium height. On the V400, this is approx. 34 cm from the lower or upper bearing roller of the timing belt. I have stuck a mark on the printer frame as a reference.

A higher belt tension can be set by adding more 50 cent coins, and a lower belt tension can be set by removing 50 cent coins.

There are two variants to choose from - one with the weight on the right-hand side and one with the weight on the left-hand side.

The tool for adjusting the timing belt tension can also be used for the FLSUN Super Racer (SR), as the timing belt spacing is the same as for the V400. The measurement should be taken at mid-height, between the lower and upper bearing roller of the timing belt.

Use of the tool for adjusting the timing belt tension is at your own risk and responsibility. I exclude any liability.

Full speed, 4 or more walls, layer height 0.15 mm, line width 0.4 mm, infill 50 %, no supports, no brim or raft, but skirt recommended!